1. Field of the Invention
The present invention relates to a roll holder device for supporting a recording material roll and a supply magazine with the same. More particularly, the present invention relates to a roll holder device and supply magazine in which recording material to be supplied can be appropriately positioned with ease.
2. Description Related to the Prior Art
A printer is used with recording material. For example, a color thermal printer is used with thermosensitive recording paper. The recording material has a form of a recording material roll, which includes a tubular spool shaft and the recording material wound about the tubular spool shaft in a roll form. A roll holder device is used to hold the recording material roll. The combination of the recording material roll and the roll holder device is set in a supply magazine, or directly in a supply chamber of the printer.
The roll holder device includes a pair of paper holder components, each of which is constituted of a holder core and a bearing member. The holder core is inserted in, and fitted inside, an axial end of the tubular spool shaft of the recording material roll. The bearing member supports the holder core in a rotatable manner. The bearing member is fitted in, and secured to, a cutout formed in a holder frame, which is an element included in the supply magazine or the supply chamber of the printer.
To supply the recording material with high precision, it is necessary that the holder core of the paper holder components should be firmly fitted in the tubular spool shaft, and a relative position of the recording material roll relative to the bearing member should be constant as predetermined. If fitting of the holder core on the tubular spool shaft is insufficiently firm, the roll holder device is likely to drop from the tubular spool shaft in setting the recording material roll into the supply magazine or the like. In contrast, if fitting of the holder core on the tubular spool shaft is excessively firm, the roll holder device is highly difficult to unload from the recording material roll.
In setting the recording material roll into the supply magazine, it is likely that turns of the recording material become loose, or the turns at an end face of the recording material roll become shaped conically without a neatly flat shape. To prevent such problems, an adhesive tape is used to secure a front edge of the recording material to the outside of the recording material roll. It is necessary to remove the adhesive tape after the recording material roll is set into the supply magazine. However, an inadvertent user is likely to forget the removal upon setting the recording material roll. If the printer is operated for supply of the recording material with the adhesive tape kept attached, no recording material is supplied. Furthermore, a mechanism for paper supply is likely to be broken in the printer or the supply magazine.
The roll holder device according to the prior art includes the paper holder components having an equal size. If the paper holder components are set on the end faces of the recording material roll in either orientation, the roll holder device can be set in the supply chamber or the supply magazine. A problem arises in failure in supply of the recording material because of a situation where the recording material roll is set in the supply magazine in a direction opposite to a proper direction.
Another problems lies in that propriety in a fitted state of the paper holder components into the tubular spool shaft cannot be checked readily. The paper holder components are likely to be set in a halfway inserted state at the supply magazine or the printer. It is conceivable that a plate spring is used in the supply magazine or the supply chamber of the printer for pressing an end face of the paper holder components to position the same in the axial direction. If the recording material roll is set with the paper holder components oriented improperly, the plate spring is deformed. There occurs an offset state of the recording material roll in the width direction.
Furthermore, a pad with a felt member is provided in the roll holder device, and pressed against the holder core for application of rotational load. This is for the purpose of applying back tension to the recording material, and preventing oblique movement or jamming of the recording material by increasing reliability in the feeding. However, the pad causes application of rotational load also in the course of winding the recording material back to the recording material roll. In the course or rewinding, there occurs a problem of looseness between turns of the recording material in the recording material roll because a considerable difference occurs in an angular speed between the inner turns and the outermost turn.